Multi-circuit electrical connectors for a printed circuit board typically include a plurality of electrical contact members or terminals disposed within a unitary dielectric housing, normally a molded plastic housing in which the terminals are inserted following molding. In these connectors, the housing typically surrounds portions of the terminals adjacent the printed circuit board to provide rigid support for the terminals.
Telecommunications equipment, computers and other electrical apparatus often include arrays of interconnected circuit boards. Each circuit board is formed by a rigid planar substrate with a plurality of integrated circuit chips and/or other electronic circuitry disposed thereon. This circuitry is connected to conductive regions or contact pads along one edge of the planar substrate to enable engagement of these circuit boards with a connector mounted on another circuit board. In this context, the circuit board on which the connector is mounted typically is referred to as the mother board. The board inserted in the connector typically is referred to as a daughter board, an edge card, a circuit module or other known terminology such as a SIMM (single in-line memory module).
A typical prior art connector houses a plurality of electrically conductive terminals. Each terminal includes a board mounting portion, such as a solder tail, which is soldered or otherwise connected to circuitry on the mother board, and a mating portion for electrically contacting a specific conductive edge contact pad on the daughter board. The daughter board often is removed and replaced to alter the functions that can be performed by the electrical apparatus in which the connector is associated. Additionally, the daughter board may be removed if any of the many circuits thereon fail or to facilitate trouble-shooting elsewhere in the electrical apparatus.
Prior art edge connectors, broadly employ two types of terminal arrangement. In one arrangements, "unitary" terminals or contact members are closely spaced, side-by-side in a linear array running the length of the connector. The unitary terminals have two contact portions, usually in the form of spring contact arms, which engage contact pads on both opposite sides of the daughter board. This provides a redundant engagement to each of the two commoned contact pads, one on each side of the board. Other arrangements employ "split" terminals or contact members wherein two separate and distinct terminals are used instead of the unitary terminal. Each one of the split terminals has only one contact portion or spring contact arm for engaging a contact pad on only one side of the daughter board. This electrically isolates the contact pads on opposite sides of the board so that additional electronic components can be mounted thereon.
A problem with having two different types of terminal arrangements, as described immediately above, is that different housings normally are used for the different terminal arrangements. This significantly increases tooling costs. It would be highly desirable to provide "split" terminals which can be inserted into the same housing which accepts "unitary" terminals. For instance, there exists literally millions of dollars of tooling for connectors using unitary terminals which could be retained and used if constructed to accept split terminal arrangements. The present invention is directed to that end and to solving the problems discussed above.